Hey all,

I was having a small backfire happen around 3k rpms and up on the boat (carb 502). I took the carb off and am cleaning it now, changing fuel, etc... but also looking at the ignition side too.

I'm trying to figure out what I have for ignition (bought the boat a few years ago as is) ... and based off the picture of it I think it's a Davis Unified Ignition - Marine Performance D.U.I. Distributors



My Question is... is there a rebuild/tune up kit (cap/rotor) for this? I'm assuming the top piece is the "ignition coil" and can get seperate.... what do I need to check look for with this kind of distributor to make sure it's not a cause of my backfiring.

Appreciate any info/insight someone can give me on this type of distributor... it's new to me.

That is a gm automotive dist non marine.

Okay thank you for the ID help. Are most running a marine grade? Is there value in swapping this one out or ?

The value is that a marine distributor has spark protection and won't cause an explosion.
They are vented and have screen on the bottom.

Now I know... I'll get it swapped. Thanks

I don't know how much benefit you get from running vacuum advance also.

Had issues with my MSD marine and bought a DUI marine from Summit. Works great! looks exactly the same as a stock GM Automotive but it's Marine with a blue cap. Only a couple hundred buck and drops right in.

Was looking at doing a Pertronix Flame-Thrower Marine Billet distributor and Flamethrower II coil and ditching the GM HEI setup and no vac advance.

That's definately a HEI auto distributor.

I like the simplicity of the HEI DUI distributor being it has 1 wire hook up and no separate coil to mount. Also you can buy the ignition module , intetgrated coil, or distibutor cap at any auto parts store anywhere